The present invention relates to a steering wheel adapter for connecting a function unit to a steering wheel.
To steer a motor vehicle by means of a steering robot, or to measure steering movements or steering forces by means of a measurement steering wheel, an apparatus is required whereby a function unit (a drive or measuring device) is connectable to the steering wheel of the motor vehicle. This device is referred to as a steering adapter.
Robot drivers are known that incorporate connection elements to the steering wheel, Such drivers are disclosed, e.g., in EP 0 235 333, EP 0 236 518 B1, and DE 39 40 588. The robot drivers presented there, however, are used for the automated actuation of the pedals of the motor vehicle; the structural connection to the steering wheel in these cases serves exclusively to support the robot driver and hold it securely positioned.
U.S. Pat. No. 3,999,425 discloses a device for emission testing for a motor vehicle, wherein an activator for the accelerator is held by means of a rod between the steering wheel and floor plate. Here, too, the steering wheel rim serves as a mechanical counter support for a measuring apparatus. The steering wheel is not moved in the process, and the transfer or measurement of torques is of no importance for the purpose at hand of measuring the exhaust emission.
DE 33 03 588 A1 discloses a robot driver, which is designed also as a steering robot, wherein the steering wheel is actuated by means of a friction roller, which is driven and pressed against the outside of the steering wheel by a pneumatic cylinder. A torque for steering the motor vehicle is thus directly transmitted to the steering wheel from the outside.
U.S. Pat. No. 3,465,577 discloses a similar solution, namely a steering robot wherein a motor is used to exert a torque onto the outside of the steering wheel rim by means of two rollers.
U.S. Pat. No. 5,865,266 discloses a steering robot whose turning shaft is coupled to the steering wheel by means of an adapter. The torque transmission takes place by means of a screw connection of the adapter directly to the steering shaft.
U.S. Pat. No. 3,889,527 discloses a steering adapter that serves to receive a measuring device for measuring the deflections of a steered front wheel and connects this measuring device to the steering wheel. The steering adapter in this case moves with the steering wheel. Since this is merely a measuring device for the turning angle, a frictional connection between the steering adapter and steering wheel is not required and it is accordingly sufficient to suspend the steering adapter by means of an arc-shaped hanging mechanism at the top of the steering wheel, and to create, by means of components with a rubber cover that laterally project beyond the steering wheel and rest on top of the steering wheel, sufficient frictional engagement so that the measuring device can follow the steering movements via the steering adapter.
A basic problem in the design of a steering adapter lies in the fact that an adaptation to individual steering wheels must be possible in a simple manner also in the case of robot drivers where a torque transfer must take place from the steering adapter to the steering wheel, taking into account that specific groupings of actuation levers and switching elements (windshield wiper lever, lever-type light switch, automatic transmission shift levers, etc.) are typically disposed in the immediate vicinity of the steering wheel rim, limiting access to the steering wheel.